In general, an electrophotographic image forming apparatus includes a drum unit, a developing unit, a laser scanning unit, and a transfer device. For example, the drum unit includes a photoconductor, a charging device, and a drum cleaning device. In addition, a tandem-type image forming apparatus includes a plurality of drum units and a plurality of developing units.
The temperature of the photoconductor rises due to the following factors: a voltage is applied from the charging device; a laser beam is irradiated from the laser scanning unit; and the photoconductor is scraped by a blade of the drum cleaning device.
When the temperature of the photoconductor rises excessively, the developing performance is degraded. As a result, the image forming apparatus is provided with an air blower that sends air for cooling the drum unit or the like.
In addition, there is known a tandem-type image forming apparatus that includes a duct that branches from the air blower to a plurality of drum units (see, for example, PTL 1).